However perfect the emergency medical service might be now or in the future, it can still come too late in cases of cardiac arrest or respiratory failure. It is a matter of only 3 to 5 minutes, that is the time span between the clinical death which is reversible and irreversible damage to the central nervous system and several other organs characteristic of biological death. Any meaningful help can only come from people who happen to be close to the site of the accident.
Practical application of life saving techniques has proved to be extremely effective in the street, on the shore, at home, at an enterprise, and in other places. Many thousands of lives saved by emergency resuscitation methods is an excellent example of this.
Statistical data demonstrate that in the United States alone over 25 thousand people were saved by the end of the 60s by persons having no medical background. It is therefore important socially and otherwise that as many people as possible are trained to perform uncomplicated but effective life saving techniques.
It should be pointed out that such training without practical experience, with practicing on specially designed life saving training devices is extremely inefficient. A person cannot acquire proper skills usable in emergency situations. Practical experience has demonstrated that the practicing process can only be made effective when training devices are employed, which can simulate a real life situation and produce a stable dynamic stereotype of movements required for the trainees to be able to successfully perform on the site of an accident without any special equipment.
Known in the art is a device for practicing techniques of cardiac-pulmonary resuscitation (cf., FRG Pat. No. 2144931, filed Sept. 8, 1971, C1. G 09 B 23/32), comprising a human manikin composed of a head mock-up equipped with a movable lower jaw, a nose with compressible nostril wings, an infection protection system made as a detachable face mask, a resilient bag placed inside the head mock-up and communicating with the mouth and nose openings; a neck mock-up hinged to the head mock-up and a mock-up of the trunk without the upper and lower extremities with a rib cage equipped with resilient elements arranged beneath the front wall and lungs simulated by a resilient container connected by an air duct to the head mock-up inner space. This training device is used by an instructor to teach trainees techniques of cardiac-pulmonary resuscitation, including assisted respiration and external chest massage. For artificial respiration the trainee brings the head of the manikin back, clamps the nostril wings, and, fitting his mouth over the manikin's mouth, vigorously exhales. The air breathed in fills the elastic bag which expands and forces the air from the mock-up head into the elastic container of the manikin's lungs. The elastic container simulating the lungs lifts the front wall of the manikin's rib cage. The trainee can see if artificial respiration is being done properly by this rise of the rib cage. For external chest massage the trainee places his both hands on the rib cage of the manikin and starts regular pressing. In this case only the instructor can judge if the trainee is doing his job properly.
This training device is deficient in that it has to be equipped with a large number of masks and elastic bags for individual protection, which does not fully exclude infection foci being formed inside the manikin considering imperfect quality of elastic bags and inaccurate fitting of such bags inside the manikin's head mock-up.
Moreover, this device provides no means for monitoring such obligatory reanimation parameters as the volume of intake air, air penetration into the stomach when the head of the mannequin is not sufficiently forced back, the number of ventilation excursions per time unit, force of heart compressions, number of heart compressions per unit of time. The trainee cannot therefore make a self-analysis of his actions and master the skill of controlling the volume of inbreathed air, the force and rate of compressions during cardiac massage..
Also known in the art is a device for practicing techniques of cardiac-pulmonary resuscitation (cf., Swedish Pat. No. 343419, C1. G 09 B 23/20, filed Nov. 10, 1958), comprising a manikin made up of a head mock-up with a nasal-oral cavity, a flexible lower jaw, a nose with flexible nostril wings, and a protection system made as a mask applied on the face area of the manikin's head mock-up; a neck mock-up equipped with a device for constricting the air ducts and hinged with the mock-up of the head and with the mock-up of the body trunk having an elastically deformed front wall, lungs simulated by an elastic container connected by the air duct with the nasal-oral cavity and the abdomen having a movable front wall, and a stomach located below this front wall and made as another elastic container connected by an air duct with the nasal-oral cavity of the head mock-up.
An instructor should necessarily supervise training in artificial respiration and external cardiac massage on this device.
To perform artificial respiration the trainee has to tilt the head back. The air duct of the stomach cavity is constricted, while the air duct of the lung cavity is released. The trainee then presses together the nostril wings and makes an energetic expiration into the manikin's mouth. The air breathed into the nasal-oral cavity is forced into the lung cavity of the dummy. The trainee can control the artificial respiration procedure by observing the rise of the front wall of the dummy rib cage. If the head of the dummy is not forced back enough, the air duct to the lungs is constricted while the air duct to the stomach is released, and the air breathed in enters the stomach cavity of the manikin and lifts the front wall of the dummy abdomen. The trainee can, therefore, notice the movement of the front wall of the abdomen and realize he is not doing properly. To perform external chest massage the trainee places his hands on the front wall of the dummy rib cage and makes rhythmical compressions.
This device, as compared to the previous one, provides an additional advantage which consists in that the trainee can, without the instructor, check if artificial respiration is performed properly by the visible movement of the front wall of the dummy abdomen. However, quantitative parameters of resuscitation, such as the volume of intake air and the pressure exerted during chest massage, cannot be monitored. The pulse is not simulated at all. No indication is given as to the skeletal integrity of the manikin rib cage in case the trainee's hands are misplaced. This reduces the efficiency of training in techniques of external cardiac massage and artificial respiration.
This prior art device is also deficient in that it provides no indication of air penetrating into the dummy stomach when it is forced into the lungs. This makes training in artificial ventilation of lungs less effective. The device also provides no indication of the duration of basic resuscitation procedures, such as duration of ventilation excursion during artificial respiration, duration of heart compression during external cardiac massage, duration of intervals between the ventilation excursion and heart compression when artificial respiration and external chest massage are performed simultaneously. In other words, one of the vital factors in emergency life saving techniques, the time factor, is not taken into consideration.
Also well known in the art is a simulator for practicing emergency life saving techniques, including assisted respiration and external cardiac massage, manufactured by Ambu (CPR Simulator, Advertising booklet, 1984, Denmark), which possesses many features of the proposed training device. This simulator is the closest prior art device.
This simulator is a manikin connected to monitoring instruments recording circulation parameters, including a hemoglobinometer, an oxyhemometer, and manometers measuring the applied pressure and the lung expanding force. The manikin is a torso with a head but devoid of the upper and lower extremities, and a mock-up of the rib cage. The head mock-up includes dispensable nose-and-mouth masks ensuring protection against cross infection of trainees. The manikin of the simulator is also equipped with a simulator of forced pulse in the area of the carotid arteries, a simulator of the xiphoid cartilage or metasternum, a detector of hand position and compression depth during heart compressions. This simulator can be used to practice mouth-to-mouth and mouth-to-nose resuscitation and cardiac massage. Filling of the rib cage and abdomen is simulated by elastic containers installed in respective locations and connected by air passages to the cavity in the simulation head of the manikin. It should be noted that this simulator is deficient in that it provides only partial control or no control at all over such erroneous actions as:
incorrect position of the manikin head during insufflation; the trainee and his instructor cannot find the reasons of ineffective artificial respiration, particularly of inflation of the stomach;
dangerous position of trainee's hands on the chest of the manikin during external heart massage, which in real life conditions may be the reason of fractures of the breast bone, ribs, heavy injuries to internal organs in the rib cage; the trainee cannot master the technique of external heart massage by himself;
leaving the manikin abdomen constrained by clothing which limits the freedom of movement of internal organs in the abdominal cavity; in real life conditions this can lead to extremely serious injuries to these organs during external heart massage.
This simulator cannot be used to train people in removing the air from the stomach of the victim. In practice, the air in the stomach prevents lungs from inflating, may cause regurgitation of the stomach contents and obstruction of the upper respiratory tracts.
This prior art simulator is also deficient in that it provides no opportunity for the trainees to assess the effectiveness of their manipulations by evident spontaneous indications of revivification (visible movements of the front wall of the rib cage, pulse, pupil contraction) and provides no means for the analysis of the revivification situation corresponding to the real life situation. The efficiency of training, particularly in non-medical groups, is therefore not sufficiently high.
This prior art simulator provides no opportunity for a large audience to participate in the teaching process by watching functioning models of basic internal human organs, such as brain, heart, lungs, upper respiratory tracts, stomach, which are adequate to the manipulations with the manikin. The teaching process cannot be made expedient for a large number of people and their knowledge of the life saving techniques are only superficial without understanding of the pathophysiological situation of human terminal states.
Moreover, this simulator has no devices for assessing the actions of trainees and automatic evaluation of their performance on the basis of time of the number of errors. The teaching process cannot, therefore, be self-instruction. The assessment cannot be made objective.
These drawbacks reduce the efficiency of training in emergency life saving techniques, this training becomes actually a conventional type of practicing where much depends on the skill of the instructor.